Receptor Antagonist

Receptor Antagonist

A Receptor Antagonist is a type of pharmaceutical drug that inhibits or reduces the activity of a biological receptor in the body. These drugs are often used in the treatment of various diseases and conditions, including hypertension, allergies, and psychiatric disorders.

Mechanism of Action

Receptor antagonists work by binding to the active site of a receptor without activating it, thereby blocking the binding of endogenous ligands or other drugs. This prevents the receptor from triggering a cellular response, effectively inhibiting its function. The degree to which a receptor antagonist inhibits a receptor's activity can vary, and is often classified as either competitive or non-competitive.

Competitive Antagonists

Competitive antagonists compete with endogenous ligands or other drugs for the same binding site on the receptor. The presence of a competitive antagonist can be overcome by increasing the concentration of the agonist, as the two substances are competing for the same site.

Non-Competitive Antagonists

Non-competitive antagonists bind to a different site on the receptor than the agonist. This changes the receptor's shape and prevents the agonist from binding, regardless of its concentration. Non-competitive antagonists are often irreversible, meaning they permanently inhibit the receptor's function.

Therapeutic Uses

Receptor antagonists have a wide range of therapeutic uses. For example, H1 receptor antagonists, also known as antihistamines, are used to treat allergies by blocking the action of histamine at the H1 receptor. Beta blockers, or beta-adrenergic receptor antagonists, are used to treat conditions such as hypertension and angina by blocking the action of adrenaline and noradrenaline at the beta-adrenergic receptors.

Side Effects

Like all drugs, receptor antagonists can have side effects. These can vary widely depending on the specific drug and the receptor it targets, but common side effects can include drowsiness, dry mouth, and dizziness. It's important for patients to discuss potential side effects with their healthcare provider before starting treatment with a receptor antagonist.

See Also

• Agonist
• Inverse agonist
• Partial agonist
• Allosteric modulator